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How to Become a Network Guru

Switches and Hubs

Why Switch? Why Hub?

The short story is that a switch is better because it allows any port to use the complete bandwidth (100BaseT, etc.) of the switch, as opposed to hubs that split the bandwidth across all ports. Switches also better handle different network speeds, so that two higher speed devices (100BaseT, for example) use the higher speed when talking to each other, even if they need to use 10BaseT to talk to slower devices.

Switches used to be significantly more expensive than hubs, but the price difference has dropped considerably in the last couple of years so that you should now be able to pick up a multi-port 10/100BaseT switch for $50 or less. Most home networks probably won’t see a difference in performance between a hub and a switch, because home network use is very sporadic compared to the business world, where connections are constantly in use.

How Much Faster Is 100BaseT (or 1000BaseT) Than 10BaseT?

Although the numbers increasing by a factor of 10 seem to imply performance leaps of 10, that’s not actually the case. Typically, 100BaseT runs four to five times the speed of 10BaseT in a similar network configuration. There are so many factors involved in the typical network that it’s almost impossible to determine how fast it should be running (better to focus on a comparison of before and after).

What’s the WAN Port for on My Hub/Switch?

WAN stands for Wide Area Network and allows the hub to connect to other networks, typically other switches or “upstream” connections. When you use a hardware router to share a high-speed Internet connection (cable, DSL, etc.), you typically connect the high-speed modem to the router’s WAN port.

LocalTalk and G3/G4 Macs

Built into all Mac models from the Plus to the beige G3s and Wallstreet PowerBooks, LocalTalk was the original method of Macintosh networking. Though it was slow (about 20 kilobytes per second), its ubiquitous nature made it the choice for the casual network user until Ethernet prices finally came to Earth in the last couple of years. Since LocalTalk used the Mac serial (printer and modem) ports to communicate, this networking option was abandoned with the debut of color-case Macs in 1998. The beige desktop G3s were the last new model to use LocalTalk, but even they didn’t use it well. You had to download a software update (LocalTalk G3) from the Apple site to fix a multitude of printer and connection problems that cropped up after the initial release.

Although LocalTalk is gone from new Macs, there are still a great number of systems out there that use it, usually because an Ethernet upgrade is either unavailable or prohibitively expensive. LaserWriters are still common in home and business, and many models require LocalTalk connectivity.

The easiest way to connect LocalTalk devices to a Mac without serial ports is to obtain a hardware LocalTalk-to-Ethernet adapter, which translates the network signal in both directions without extra effort on your part. The main difficulty here is adapter availability, as the adapters have become scarce with the passing of LocalTalk from the new computer scene. Your best bet for older hardware are sites like MacResQ or the auctions of eBay. Since the types of adapters varies, get as many details about what you’re buying as possible, to make sure you end up with the right thing.

Software is also an option here, as Apple provides a control panel (and free download) called LocalTalk Bridge that will connect an Ethernet and LocalTalk network. The downside of this is that you need to have a computer capable of connecting to both networks that can act as an intermediary. If you only have an Ethernet Mac, LocalTalk won’t do you any good.

Reader Comments (20)

Your statement "Since LocalTalk used the Mac serial (printer and modem) ports to communicate..." is incorrect. LocalTalk only works through the Printer port, since that is the only serial port that passes AppleTalk info. You cannot use the modem port for LAN communications. Otherwise, your article is well done!

Manu - The How Stuff Works web site is always a good place to start. I found a section that explains switched hubs (or switches). Be sure to follow the "next page" links, as the article is a couple pages long.

Does anyone have experience using a Category 6 ethernet cable with a Mac G4 Cube? When I use a Cat6 cable, my Mac freezes during startup (it looks like the extensions aren't even loading). The Cat5 that came with my cable modem works fine.

Fanzy - while real-life numbers differ quite a bit, 10baseT specs are that it can carry 10 megabit speeds and 100baseT can carry 100 megabit speeds (10 times faster). Many computers are now sporting 1000baseT (gigabite) ethernet. Again, though, real-life throughput doesn't even nearly reach this, but 100baseT is still much faster than 10baseT. However, setting yourself up with 100baseT doesn't automatically mean you'll get huge speed improvements on your network. If you are moving files between computers in your home or office (in other words, your local network), then yes, you certainly want to put in 100baseT or better. But if the only thing you use your ethernet connection for is internet connection, 100baseT will not give you any improvement at all. Remember, I said 10baseT supposedly handles up to 10 megabit speeds. Nearly all broadband services are only giving you a maximum of 1 or 2 megabit speeds—far below the capacity of a 10baseT line.

George - in my opinion, hubs are obsolete. It's probably very difficult to even find a plain hub for sale any more.

In reality, a switch is a hub. More accurately, it's a hub on steroids. The purpose of both devices is to allow multiple devices to communicate together via ethernet connections and/or allow an incoming network (i.e. internet) connection to be shared among all the attached devices.

The problem with a nonswitched hub is that all traffic gets sent to every single attached device. This results in data "colliding" with each other and significantly reduced performance.

A switched hub solves this problem by having technology to deliver packets of data only to the device it was intended for. Since this is the ideal scenario anyway, you'll see why there's really no reason to use/buy/sell a legacy hub.

And, for what it's worth, pretty much any broadband router that has multiple jacks for connecting computers has a switched hub built in.

Thanks for your note. Some old Mac OS versions (System 7, I think) allowed you to choose either the modem or printer port for LocalTalk. Sounds like they eventually (wisely) limited it to printer-only. You could probably have counted the people who picked "modem" on one hand!

Need someone to explain me the following:I have an industrial system with data logins - 2 slave nodes and master (which is an HMI screen). Each one has 1 Ether port and I want to connect all this mess to internet to display data on desk PC. Do I need switch only (3 in and 1 out)or router, or router only (3 in 1 out), or switch 3 in 1 out and 1 in 1 out router (with firewall...).

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